Allen Walker: ♥. Just ♥. Allen's the one who always comes back for her, especially when he shouldn't, and she'll be the first to tell him how ridiculous it is to rescue a guardian. But for that and everything else they've been through together, she'll stick by him forever. Fou really does think he's a moron (for reasons, see above), but in an incredibly silly sort of way that she's developed a fondness for. She doesn't know if she's necessarily the best for him, but she's the only one that she's certain will keep his best interests at heart.
Lina Inverse: It was a rocky start, but Fou's come to accept Lina as something... tolerable. At the very least, she knows she can count on Lina to back her up if need be. Fou also views her as a bit of a friendly rival for no reason in particular. She'll make a reason if she has to.
Lenalee Lee: Oh boy. Despite their history, Fou's pretty cool with Lenalee now. She doesn't know what changed in the girl, but she likes it -- especially that Lenalee's talking to Allen again. Just for that, Fou'll let bygones be bygones.
Maes Hughes: DIAF. In theory, he's not that bad of a guy, and she actually has a fair amount of respect for him. However, he also has a certain talent for annoying the shit out of her. Still, somehow they manage to have tolerable moments.
Alphonse Elric: He's a nosy little twerp who enjoys butting in on other people's business far too much. Despite that, though, she has a great deal of respect for him and his abilities as a medic, and after seeing him take care of Allen she feels just a bit indebted to him.
Yuffie Kisaragi: Yuffie has that air of a tough girl that can take care of herself, which Fou definitely approves of, but she's still definitely a kid.
Miyazawa Yukino: FOU HAS NO IDEA WHAT TO MAKE OF HER. Fou likes to think that she doesn't like a bothersome girl like Yukino, but what she thinks and what she really feels doesn't always match up.
Rikugou Tokidoki and
Aang: Two kids that Fou gets a kick out of teasing, and that put up with her abrasiveness fairly well. She's almost like a really really evil big sister. Fou's pretty amused by Toki's flailing, so she might call him up for "training" when she's bored.
Cielo: Airhead. But at least he's an airhead with a backbone. Those hookers under his protection are still doomed, though.
Miyu: Another girl Fou's not sure what to make of, but for very different reasons. She's keeping a wary eye on the vampire, and while she's starting to not mind Miyu so much, she's still a potential threat.